ELECTRONIC STRUCTURE AND MOLECULAR PROPERTIES OF BORON HYDRIDE IN ITS GROUND AND EXCITED STATES

Ab initio wave functions have been constructed for the lowest 1Σ+, 1π, 3π, 1Σ-, 3Σ-, 1Δ, 3Δ, and 3Σ+ states of BH as a function of the internuclear separation. The valence bond approach was employed and full configuration interaction within the valence shell was carried out. A Gaussian-lobe function representation of the boron and hydrogen atomic orbitals was employed. Our best function for the 1Σ+ state of BH, at the experimental equilibrium separation of 2.336 Bohrs yields an energy of -25.1426 au (dipole moment 0.702 au) while at the predicted separation of 2.536 Bohrs the energy is -25.1456 au (dipole moment 0.603 au). The vertical transition energies at the experimental internuclear separation are: 1Σ+ (0.00 eV), 3π (0.77 eV), 1π (2.90 eV), 3Σ- (4.07 eV), 1Δ (6.01 eV). The dipole moment, quadrupole moment and electric field gradient at the B nucleus and at the H nucleus are reported for the bound states for three internuclear separations. © 1969.